Using the History panel

You can use the History panel to jump
to any recent state of the image created during the current working
session. Each time you apply a change to an image, the new state
of that image is added to the panel.

For example, if you select,
paint, and rotate part of an image, each of those states is listed
separately in the panel. When you select one of the states, the
image reverts to how it looked when that change was first applied.
You can then work from that state.

You can also use the History
panel to delete image states and, in Photoshop, to create a document
from a state or snapshot.

To display the History panel, choose
Window > History, or click the History panel tab.

Photoshop History panel

A.
Sets the source for the history brush B.
Thumbnail
of a snapshot C.
History state D.
History state
slider

Keep
the following in mind when using the History panel:

Program-wide changes, such as changes to panels, color settings,
actions, and preferences, are not reflected in the History panel,
because they are not changes to a particular image.

By default,
the History panel lists the previous 20 states. You can
change the number of remembered states by setting a preference under
Preferences > Performance. Older states are automatically deleted
to free more memory for Photoshop. To keep a particular
state throughout your work session, make a snapshot of the state.

Once you
close and reopen the document, all states and snapshots from the last
working session are cleared from the panel.

By default, a snapshot of the initial state of the document
is displayed at the top of the panel.

States are added to the bottom of the list. That is, the
oldest state is at the top of the list, the most recent one at the
bottom.

Each state is listed with the name of the tool or command
used to change the image.

By default, when you select a state, the states below it
are dimmed. This way you can easily see which changes will be discarded
if you continue working from the selected state.

By default, selecting a state and then changing the image
eliminates all states that come after it.

If you select a state and then change the image, eliminating
the states that came after, you can use the Undo command to undo
the last change and restore the eliminated states.

By default, deleting a state deletes that state and those
that came after it. If you choose the Allow Non-Linear History option,
deleting a state deletes only that state.

Revert to a previous image state

Do any of the following:

Click the name of the state.

Choose Step Forward or Step Backward from the History
panel menu or the Edit menu to move to the next or previous state.

Delete one or more image states

Do
one of the following:

Click the name of the state, and choose
Delete from the History panel menu to delete that change and those
that came after it.

Drag the state to the Delete icon to
delete that change and those that came after it.

Choose Clear History from the panel menu to delete
the list of states from the History panel, without changing the
image. This option doesn’t reduce the amount of memory used by Photoshop.

Hold down Alt (Windows) or Option (Mac OS),
and choose Clear History from the panel menu to purge the list of
states without changing the image. If you get a message
that Photoshop is low on memory, purging states is useful, because
the command deletes the states from the Undo buffer and frees up memory.
You can’t undo the Clear History command.

Choose Edit > Purge > Histories
to purge the list of states for all open documents. You can’t undo
this action.

Create or replace a document with
an image state

Do one of the following:

Drag a state or snapshot onto the Create
a New Document From Current State button in
the History panel. The history list for the newly created document
contains only the Duplicate State entry.

Select a state or snapshot, and click the Create
a New Document From Current State button . The
history list for the newly created document contains only the Duplicate
State entry.

Select a state or snapshot, and choose New Document
from the History panel menu. The history list for the newly created
document contains only the Duplicate State entry.

Drag a state onto an existing document.

To save one or more snapshots or image
states for use in a later editing session, create a new file for
each state you save, and save each in a separate file. When you reopen
your original file, plan to open the other saved files also. You
can drag each file’s initial snapshot to the original image to access
the snapshots again from the original image’s History panel.

Set history options

You can specify the maximum number of items
to include in the History panel and set other options to customize
the panel.

Choose
History Options from the History panel menu.

Select an option:

Automatically Create
First Snapshot

Automatically creates a snapshot of the initial state
of the image when the document is opened.

Automatically Create New Snapshot When Saving

Generates a snapshot every time you save.

Allow Non-Linear History

Makes changes to a selected state without deleting the
states that come after. Normally, when you select a state and change
the image, all states that come after the selected one are deleted.
In this way, the History panel can display a list of the editing
steps in the order that they were made. By recording states in a
nonlinear way, you can select a state, make a change to the image,
and delete just that state. The change is appended at the end of
the list.

Show New Snapshot Dialog By Default

Forces Photoshop to prompt you for snapshot names even
when you use the buttons on the panel.

Make Layer Visibility Changes Undoable

By default, turning layer visibility on or off is not
recorded as a history step and therefore can’t be undone. Select
this option to include layer visibility changes in history steps.

Set Edit History Log options

You may need to keep careful track of what’s
been done to a file in Photoshop, either for your own records, client
records, or legal purposes. The Edit History Log helps you keep
a textual history of changes made to an image. You can view the Edit
History Log metadata using Adobe Bridge or the File Info dialog
box.

You can choose to export the text to an external log
file, or you can store the information in the metadata of edited
files. Storing many editing operations as file metadata increases
file size; such files may take longer than usual to open and save.

If you need to prove that the log file hasn’t been
tampered with, keep the edit log in the file’s metadata, and then
use Adobe Acrobat to digitally sign the log file.

By default,
history log data about each session is saved as metadata embedded in
the image file. You can specify where the history log data is saved
and the level of detail contained in the history log.

Make a snapshot of an image

The
Snapshot command lets you make a temporary copy (or snapshot)
of any state of the image. The new snapshot is added to the list
of snapshots at the top of the History panel. Selecting a snapshot
lets you work from that version of the image.

Snapshots are
similar to the states listed in the History panel, but they offer additional
advantages:

You can name a snapshot to make it easy to identify.

Snapshots can be stored for an entire work session.

You can compare effects easily. For example, you can take a snapshot before and after applying a filter. Then select the first snapshot, and try the same filter with different settings. Switch between the snapshots to find the settings you like best.

With snapshots, you can recover your work easily. When you experiment with a complex technique or apply an action, take a snapshot first. If you’re not satisfied with the results, you can select the snapshot to undo all the steps.

Note:

Snapshots are not saved with the image—closing an image deletes its snapshots. Also, unless you select the Allow Non-Linear History option, selecting a snapshot and changing the image deletes all of the states currently listed in the History panel.

Create a snapshot

Select a state and do one of the following:

To
automatically create a snapshot, click the Create New Snapshot button on
the History panel, or if Automatically Create New Snapshot When
Saving is selected in the history options, choose New Snapshot from
the History panel menu.

To set options when creating a snapshot, choose
New Snapshot from the History panel menu, or Alt-click
(Windows) or Option-click (Mac OS) the Create New Snapshot
button.

Enter the name of the Snapshot in the Name text box.

Choose the snapshot contents from the From menu:

Full Document

Makes a snapshot of all layers in the image at that state

Merged Layers

Makes a snapshot that merges all layers in the image
at that state

Current Layer

Makes a snapshot of only the currently selected layer
at that state

Work with snapshots

Do one of the following:

To
select a snapshot, click the name of the snapshot or drag the slider
at the left of the snapshot up or down to a different snapshot.

To rename a snapshot, double-click the snapshot
and enter a name.

To delete a snapshot, select the snapshot and either
choose Delete from the panel menu, click the Delete icon , or
drag the snapshot to the Delete icon.

Paint with a state or snapshot
of an image

The History Brush tool lets
you paint a copy of one image state or snapshot into the current
image window. This tool makes a copy, or sample, of the image and
then paints with it.

For example, you might make a snapshot
of a change you made with a painting tool or filter (with the Full
Document option selected when you create the snapshot). After undoing
the change to the image, you could use the History Brush tool to
apply the change selectively to areas of the image. Unless you select a
merged snapshot, the History Brush tool paints from a layer in the
selected state to the same layer in another state.

The History
Brush tool copies from one state or snapshot to another, but only
at the same location. In Photoshop, you can also paint with the
Art History Brush tool to create special effects.

Select the History Brush tool .

Do one of the following in the options bar:

Specify the opacity and blending mode.

Choose a brush and set brush options.

In the History panel, click the left column of the state
or snapshot to be used as the source for the History Brush tool.